Halibut contains a moderate amount of mercury, averaging 0.241 parts per million (ppm) according to FDA monitoring data. That places it above low-mercury favorites like salmon and shrimp but well below high-mercury fish like swordfish and shark. The FDA and EPA jointly classify halibut as a “Good Choice,” meaning it’s safe to eat up to one serving per week, even for pregnant women and young children.
How Halibut Compares to Other Fish
Mercury levels in seafood span a wide range, and halibut sits in the middle of the pack. Here’s how it stacks up against fish you probably eat regularly:
- Shrimp: 0.009 ppm (very low)
- Salmon: 0.022 ppm (very low)
- Canned light tuna: 0.126 ppm (low to moderate)
- Halibut: 0.241 ppm (moderate)
- Shark: 0.979 ppm (high)
- Swordfish: 0.995 ppm (high)
Halibut has roughly twice the mercury of canned light tuna and about ten times more than salmon. But it contains roughly a quarter of what you’d get from swordfish or shark. In practical terms, you can eat halibut regularly without concern as long as you’re not having it every day.
Bigger Halibut Carry More Mercury
Mercury accumulates in fish over their lifetimes, so older, larger halibut tend to have higher concentrations. Research from the Institute of Marine Research in Norway found a clear pattern: no halibut under about 85 pounds exceeded EU mercury limits, while roughly one in five halibut between 130 and 500 pounds did. The FDA data reflects this variability too. While the average halibut tested at 0.241 ppm, individual fish ranged from undetectable levels all the way up to 1.52 ppm.
You typically can’t choose the size of the fish your fillet came from at a grocery store or restaurant. But if you’re buying a whole halibut or choosing cuts at a fish market, smaller fish will generally have lower mercury levels.
How Much Halibut You Can Safely Eat
The FDA and EPA place halibut in their “Good Choices” category, one tier below the lowest-mercury “Best Choices” group. The guidance is straightforward: eat up to one serving per week from the “Good Choices” list. A serving for adults is about 4 ounces (roughly the size of your palm). For children, serving sizes are smaller and scale with age.
This one-serving-per-week recommendation applies to everyone, including pregnant women, those who are breastfeeding, and young children. If you eat halibut one week, you can still have two to three servings of “Best Choices” fish like salmon, shrimp, tilapia, or cod that same week. The categories aren’t either/or. You just want to keep the moderate-mercury fish to once a week while filling the rest of your seafood meals with lower-mercury options.
Why Halibut Is Still Worth Eating
Mercury is only half the equation. Halibut is a lean, protein-rich fish that also delivers omega-3 fatty acids, the type linked to heart and brain health. Pacific halibut provides about 0.1 grams of EPA and 0.3 grams of DHA per 100 grams of fish. Greenland halibut (sometimes sold as turbot) is fattier, with roughly 0.5 grams of EPA and 0.4 grams of DHA per 100 grams.
Those numbers are lower than what you’d get from salmon or mackerel, but halibut still contributes meaningful omega-3s to your diet. The benefit of eating fish at moderate mercury levels generally outweighs the risk of mercury exposure, which is exactly why federal guidelines recommend eating it weekly rather than avoiding it. The fish to truly limit or skip are the high-mercury species: shark, swordfish, king mackerel, and tilefish from the Gulf of Mexico.
Keeping Your Mercury Exposure Low
If you enjoy halibut and want to minimize mercury intake, a few strategies help. First, treat it as your one moderate-mercury meal for the week and fill other seafood nights with low-mercury options like salmon, shrimp, sardines, or pollock. Second, vary the types of fish you eat rather than relying on halibut alone. Rotation naturally limits how much mercury from any single species builds up in your body. Third, pay attention to portion sizes. A restaurant halibut fillet often weighs 6 to 8 ounces or more, which counts as one and a half to two servings by FDA standards.
Mercury leaves your body over time, with a half-life of roughly 70 to 80 days. Occasional weeks where you eat more halibut than the guidelines suggest won’t cause lasting harm. The recommendations are designed around long-term, consistent eating patterns, not single meals.